How to replace object with keeping it dimmensions / how to change dimension of an object to scale value
My best try is 3 steps.
Replacing a cube with Suzanne, keeping exact dimensions.

Link Object Data (Ctrl + L &gt; Object Data)
Copy dimensions of the Cube to one Suzanne (it gets slightly distorted)
Select all other monkeys, and copy object scale to them (RMB &gt; Copy all to selected)

Linking Object Data, nothing new here.

Copy exact dimensions from Cube to Suzanne. And then copy the scale to the rest.